This invention relates to magnetic discs and, more particularly, to removing of magnetic coatings therefrom.
A large quantity of magnetic discs are currently being used in computer systems. These discs are used to store data at very high bit densities and must be extremely reliable in that the loss of even a few bits during computer use cannot be tolerated. Thus, the standards and specifications to which the discs are manufactured are highly rigid. During manufacture an aluminum blank disc is coated with a magnetic coating (iron oxide plus binder) and baked. Small minor defects in the coating is generally a cause for rejection and scrapping of the disc. To avoid scrapping discs which have been rejected due to defective coatings, one method used is to remove the defective coating by mechanical abrasion (grinding and honing). This procedure however results in partial destruction of the original surface of the disc in that part of the aluminum base is removed. The disc cannot then be used for its original purpose. Since the blanks cost five or more dollars each the loss due to defective coatings can be substantial.
Accordingly, it is an object of the present invention to provide an improved method for processing defective magnetic discs.
It is another object of this invention to provide an improved method for processing magnetic discs to remove the magnetic coating therefrom.
It is a further object of this invention to provide a method for processing magnetic discs to remove the magnetic coating therefrom without damaging the metal substrate.